1. Field of the Invention
The present invention relates to a dental compressed-air motor, consisting of a housing in which there is arranged a rotatably supported rotor adapted to be set into rotation by means of operational compressed air which is introduced into the housing through the intermediary of an operational compressed-air inlet conduit. The motor includes a rotor shaft connectable with a work tool, wherein the operational compressed-air inlet conduit has associated therewith a regulating device located within the housing, with an externally operable handle for effecting the turning of a rotary slide valve supported within the motor housing for variation of the rotational speed and/or the direction of rotation of the rotor. Furthermore, at one end of the motor housing there are provided coupling means for connection with a dental handpiece supporting the work tool and, at the other end of the motor housing, coupling means in the form of an attachment element for connection with a supply hose conducting compressed air or other media streaming towards or from the motor housing or handpiece. The rotary slide valve is located intermediate the motor and the attachment element and whereby the attachment element is provided with essentially axially incoming and essentially axially further extending media through-passageways which are connected to the media conduits leading to the locations of application for the compressed-air motor of the handpiece.
2. Discussion of the Prior Art
The compressed-air motor, for instance, can be constructed, in accordance with German Laid-open patent application No. 19 41 159, as a turbine with a rotor provided with turbine vanes; pursuant to German Published patent application No. 12 32 789 as a piston motor having a rotor provided with cylinders for pistons, for example, in the form of balls; or pursuant to German Laid-open patent application No. 23 04 666 as a vane motor with a rotor which is provided with slots for radially movable vanes.
A compressed-air motor of the above-mentioned type is the subject matter of earlier German patent application P No. 28 39 632.9. In this compressed-air motor, the attachment element is provided in the same manner as in the compressed-air motor which has become known through the prospectus sheet "KaVo INTRA L-Motor", by being provided in a cap screw-like coupling unit at the end of the supply hose, which can be threaded onto a thread of fixed attachment portion of the motor, whereby the attachment element and the attachment portion are drawn towards each other while producing the media transmission through the intermediary of mutually inserted plug and tube support connections. The required screwing off and screwing on of the coupling nut which is necessary for a separation and a reassembly of motor and attachment element, for example, for the purpose of interchanging differently constructed compressed-air motors, or for the purpose of the oiling or lubricating of the motor effected from the connecting side, for instance, with the aid of a spray nozzle containing a maintenance medium, is always an extremely complex and time-consuming procedure.
Accordingly, it is an object of the present invention to provide in a compressed-air motor of the above mentioned type, an arrangement for the simple and rapid separation and reassembly of the motor and attachment element.
Through German Petty Pat. No. 77 29 110 there has become known a dental compressed-air drive aggregate which, in contrast with the compressed-air motor of the above mentioned type, is not connectable with a dental handpiece supporting the work tool, but is constructed as a compressed-air turbine directly driving the work tool and fixedly built in at one end of the gripping sleeve of a dental handpiece representing a turbine handpiece. At the other end of the gripping sleeve of this known handpiece there is provided an attachment element for the connection of compressed-air or, respectively, other flow media to a supply hose leading towards or from the handpiece. This attachment element of the known handpiece is provided to facilitate a quick coupling, in essence, a simple and rapid separation and reassembly, on the one hand, of the gripping sleeve and the connecting member in addition to the supply hose, and on the other hand, with detachably insertable guide spigot at the inlet apertures of the gripping sleeve which is axially open towards the attachment side, into which there extend the media through-passageways, which presently end with outlet openings extending from the side of the guide spigot, and which are sealed relative to each other while leaving a spacing therebetween, wherein the gripping sleeve includes at the side wall of the inlet apertures, inlet openings associated with the outlet openings of the guide spigot which, for an inserted guide spigot, come into communication with the outlet openings of the latter and from which there extend media conduits leading towards a location of application for the handpiece. Due to the axial spacing and a mutual sealing of the outlet openings of the different media through-passageways, there is obtained a relatively large length for the guide spigot or extension.
The positioning of this relatively lengthy guide spigot within the gripping sleeve of the known handpiece thus presents no difficulties since guide sleeves must in any event have a predetermined length in order to facilitate a secure gripping, primarily in a type of pencil holder, which, without anything else, affords the arrangement of the inlet opening serving for the insertion of the guide spigot. Thereby, also the media conduits which lead to the drive aggregate, for example, cooling media conduits, are not in the way.
Another relationship is obtained when a compressed-air motor built in accordance with the type shown in German patent application P No. 28 39 632.9 should be provided with an attachment element with a lengthy guide spigot as is known from German Petty Pat. No. 77 29 110. In this compressed-air motor, at the hose end, for positioning the lengthy guide spigot of the attachement element, due to the rotary slide valve of the regulating device being in the way, either the entire regulating device must be omitted, or a special extension sleeve must be provided whereby for a coupled on handpiece there was obtained such a large overall length and such a high total weight, that the handpiece inclusive the compressed-air motor and attachment element would become unwiedly. The omission of the regulating device would eliminate the advantage of the capability of varying the rotatinal speed or the direction of rotation.